Overhead projector/film-based presentation has been in existence since the early 1960s. The paradigm established at that time is still with us today. Specifically, an outline is prepared and "visuals," e.g., 81/2 by 11 inch (22.times.28 cm) transparent films, are produced to help a presenter communicate a message to an audience. The visuals are typically organized in sequence together with a few notes and are often accompanied by "backup visuals" to help the presenter address unanticipated questions and audience concerns. While the technology used for making visuals has changed considerably over the years, this basic, common sense, user-friendly, "talk and show" paradigm has remained relatively constant. Indeed, the changes in printing and copying technology have dramatically changed the ways that visuals are produced.
At first, visual content was created via a typewriter and converted into visuals by a thermal transfer process (e.g., infrared transparency makers). Later, manufacturers invented machines which slowly typed out bold letters onto adhesive strips which were applied to transparent film to make the visual. Later, word processing took over for the typewriter, followed by the first-generation computers which replaced dedicated word processors. Spreadsheets, graphing, and charting capability came shortly thereafter, but the real impact came with the advent of laser printing and subsequent color printing devices which utilized ink jet and thermal mass transfer technology. These innovations, along with the greatly simplified process of making high-quality color visuals, have fueled the growth of the computer-generated transparency film market.
Software companies responded by improving the "content authoring" capabilities of word processing, charting, drawing and clip art products. This was the early start of presentation graphic software programs, such as Harvard Graphics.TM. and Aldus Persuasion.TM.. The primary objective of these software application programs was to generate high-impact charts and graphs on transparency film, paper, color laser 8.times.10 inch (20.times.25 cm) film, or laser-generated 35 mm slides.
When computer-generated visuals and presentation graphics programs became commonplace, and liquid crystal display (LCD) projection panels were developed, it did not take long for the market to realize that an expensive step of presentation preparation could be eliminated by projecting images directly from the computer, thus eliminating the need for hard copy output. This begot the early electronic presentation market. (An LCD projection panel is a device that connects to a computer and/or video source and sits atop a transmissive overhead projector and, as such, is a direct replacement/substitute for transparency film.)
Typically, the LCD panel is connected to the computer through the general purpose interface known in the industry as VGA (Video Graphics Array). Whereas VGA is a widely-accepted standard, it also has many constraints relative to the specific application of electronic presentation:
1. Power consumption. VGA is designed to drive an external display unit at a nominal resolution of 480 lines by 640 pixels, where each pixel is four bits of color, or one of 16 colors. Data transfer rates can easily exceed 20 Mbits/second. This transfer rate draws substantial power from a battery-operated computer, thereby reducing the life of the battery. Thus, from practical perspective, the unit is usually plugged into an electrical outlet when a presentation is being given. This leads to a more cumbersome setup and requires the speaker to be in close proximity to both the LCD panel and an alternating current (AC) outlet. PA1 2. Limited product migration. VGA is essentially a fixed format (640 lines.times.480 pixels) standard. It is not compatible with new higher speed, higher resolution standards and requires adapters to interface with a television (TV) monitor. PA1 3. Difficult setup. The VGA cable, designed for use with desktop computers, is physically large for mobile computing and can be somewhat cumbersome to hook-up. This extends the setup time, lowers the "comfort level" of the speaker, and makes it difficult to support multiple speakers in rapid succession, as is common in many business presentations. Furthermore, it eliminates the use of a whole class of mobile computers that do not come equipped with VGA ports (i.e., all Personal Digital Assistants (PDAs) and many sub-notebook computers). PA1 4. Limited presentation control. VGA is most often used to duplicate the computer's image onto another screen. This means that, unless additional hardware is added, the audience views the same image being shown on the presenter's computer. In this "single view" mode, the presenter is deprived of the comfortable presentation paradigm of a "stack of visuals together with speaker notes."
In order to address this last issue, some companies have developed software and accompanying hardware that converts the presenter's computer into an "electronic lectern" complete with a slide sorter, speaker notes, and a method to control what the audience sees. One company, EZ Show (Burnaby, B. C. Canada) has created software sold under the name "EZ Presenter" and an associated external graphics display card, which together provide the "electronic lectern" functionality. Another company, Software Publishing Company (SPC) of Santa Clara, Calif., U.S.A., offers a software package sold under the name "Spotlight," which also allows the presenter to have the functionality of a "presenter's lectern." The SPC System requires either a second computer or an additional internal video graphics board to be installed in the presenter's computer in order to drive the audience's display device. Most notebook computers do not have the physical room for the addition of an internal graphics display board. Whereas both of these systems offer the convenience of a presenter's lectern, they require additional hardware and are themselves based on, and thus limited by, the VGA standard.